Memory devices are electronic devices arranged to store electrical data. A plurality of memory elements can be combined in various arrangements in order to store multiple bits arranged in words or other combinations. Various electronic circuits including semiconductor devices, such as transistors, are used as memory elements. Memory elements may be classified in two main categories: volatile and nonvolatile. Volatile memory loses any data as soon as the system is turned off, thus, it requires constant power to remain viable. Most types of random access memory (RAM) fall into this category. NVM device does not lose its data when the power of the device is turned off.
Certain types of NVM devices, circuits employing floating-gate devices, high-voltage drivers and other circuits fabricated in logic CMOS require relatively high-voltages (e.g., about 20 V in a 5 V CMOS process). For example, in NVM devices, high-voltages are often used by circuits that program and erase information stored on the floating gates, and on-chip charge pumps are used for the most part to generate these high-voltages. In all these circuits, switches are required to selectively apply the high-voltages to specific circuit elements.